Described herein are systems, methods and devices for improving cardiac function, and may relate generally to the treating heart disease, particularly congestive heart failure, and more specifically, to a systems, methods, and devices for partitioning a patient's heart chamber.
Congestive heart failure annually leads to millions of hospital visits internationally. Congestive heart failure is the description given to a myriad of symptoms that can be the result of the heart's inability to meet the body's demand for blood flow. In certain pathological conditions, the ventricles of the heart become ineffective in pumping the blood, causing a back-up of pressure in the vascular system behind the ventricle.
The reduced effectiveness of the heart is usually due an enlargement of the heart. A myocardial ischemia may, for example, cause a portion of a myocardium of the heart to lose its ability to contract. Prolonged ischaemia can lead to infarction of a portion of the myocardium (heart muscle) wherein the heart muscle dies and becomes scar tissue. Once this tissue dies, it no longer functions as a muscle and cannot contribute to the pumping action of the heart. When the heart tissue is no longer pumping effectively, that portion of the myocardium is said to be hypokinetic, meaning that it is less contractile than the uncompromised myocardial tissue. As this situation worsens, the local area of compromised myocardium may in fact bulge out as the heart contracts, further decreasing the heart's ability to move blood forward. When local wall motion moves in this way, it is said to be dyskinetic, or akinetic. The dyskinetic portion of the myocardium may stretch and eventually form an aneurysmic bulge. Certain diseases may cause a global dilated myopathy, i.e., a general enlargement of the heart when this situation continues for an extended period of time.
As the heart begins to fail, distilling pressures increase, which stretches the ventricular chamber prior to contraction and greatly increases the pressure in the heart. In response, the heart tissue reforms to accommodate the chronically increased filling pressures, further increasing the work that the now comprised myocardium must perform.
Patients suffering from congestive heart failure are commonly grouped into four classes, Classes I, II, III and IV. In the early stages, Classes I and II, drug therapy is presently the most common treatment. Drug therapy typically treats the symptoms of the disease and may slow the progression of the disease, but it cannot cure the disease. Presently, the only permanent treatment for congestive heart disease is heart transplantation, but heart transplant procedures are very risky, extremely invasive and expensive and are performed on a small percentage of patients. Many patient's do not qualify for heart transplant for failure to meet any one of a number of qualifying criteria, and, furthermore, there are not enough hearts available for transplant to meet the needs of CHF patients who do qualify.
Substantial effort has been made to find alternative treatments for congestive heart disease. For example, surgical procedures have been developed to dissect and remove weakened portions of the ventricular wall in order to reduce heart volume. This procedure is highly invasive, risky and expensive and is commonly only done in conjunction with other procedures (such as heart valve replacement or coronary artery by-pass graft). Additionally, the surgical treatment is usually only offered to Class III and IV patients and, accordingly, is not an option for most patients facing ineffective drug treatment. Finally, if the procedure fails, emergency heart transplant is the only presently available option.
Mechanical assist devices have been developed as intermediate procedures for treating congestive heart disease. Such devices include left ventricular assist devices and total artificial hearts. A left ventricular assist device includes a mechanical pump for increasing blood flow from the left ventricle into the aorta. Total artificial heart devices, such as the Jarvik heart, are usually used only as temporary measures while a patient awaits a donor heart for transplant.
Other efforts to treat CHF include the use of an elastic support, such as an artificial elastic sock, placed around the heart to prevent further deleterious remodeling. Treatment of the heat by mechanical means typically requires accurate and effective placement of treatment devices. Once a treatment device is implanted, it is often difficult (if not impossible) to correct or adjust placement of a treatment device. Furthermore, removal of a treatment device may require further invasive procedures. Thus, it would be beneficial to provide device, systems and methods for removal of cardiac treatment devices that may address these problems.
Described herein are treatment devices that are configured to be removable (or repositionable), systems for removing and/or repositioning such devices, and methods of removing and/or repositioning treatment devices.